Shin & Yuri & Okechukwu are all really knowledgeable, I can't add anything to their replies.

Fundamentally Tableau works with data like a database does and Tableau likes "tidy data" where there is one attribute per column. Multi-valued cells as described here break that convention, so some sort of effort is necessary to work with them as if they are a single column, whether that is using multiple parameters or preparation of the Tableau data source or even further in the backend.

I'm interested in what your colleague is thinking of. I'm not sure what your colleague means by "dynamic sets", that term isn't familiar to me. Tableau presently has four types of sets that I'm aware of:

- manual or constant sets that we create by selecting marks in a view and choosing to add them to a set

- computed sets that are created by right-clicking on a dimension

- combined sets that are created by combining manual and/or computed sets

- user filter sets that are created using the Server->User Filter menu

Tableau v2018.3 adds a new Set Action for views where we can update sets by selecting marks.

In any case a Set is returning a boolean In/Out for each mark showing it is in the set or not. So to get all of the different combinations for 3 variables (S1, A1, C1) in any order with between 1 and 3 variables selected would require six sets, four different variables would require 14 sets, and so on. You could build a parameter to test for each of the combinations but that's not a multi-select parameter, that's a single select for the desired combination and the number of sets could quickly get very unwieldy.